Is that while both movies deal with the supernatural/magical, the Mummy deals with a supernatural unstoppable villian. The only way to defeat said villian is via finishing the quest and getting the magical artifiact. Indy on the other hand deals with real life people (nazis) who are perfectly normally humans, furthermore the hero gets his ass kicked routinely via these perfectly normal humans (thus showing off his own humanity), yet through sheer cunning/luck the hero still wins.

A second reason you should not compare the two movies is that Raiders of the Lost Arc deals with familiar imagery with the story of Moses and the Ten Commandments. It does reinvent the story somewhat via making the Ten Commandments mystical and magical. Who cares about a Book of the Dead or the Shiva Sankara Stones.